Gross negligence and willful misconduct - that's how a federal judge in New Orleans labeled the actions of BP in the nation's worst offshore oil spill. It happened in the Gulf of Mexico four years ago. The judge said reckless behavior by the company was to blame. The ruling means BP faces even stiffer penalties for the deadly Deepwater Horizon disaster. NPR's Debbie Elliott covered the oil spill and the legal fallout since. And she joins us now. And Debbie, today's decision appears to assign a significant responsibility for the disaster to BP. Explain what the judge found.

DEBBIE ELLIOTT, BYLINE: Well, U.S. District Judge Carl Barbier found that BP, as you said, acted with gross negligence and willful misconduct. Those are some pretty strong words. He said the way that the company operated its Macondo well deep in the Gulf of Mexico was a series of poor decisions and, probably more importantly, profit-driven decisions. And that that added to the risk on an already troublesome well. And it led to a blowout that killed 11 rig workers and spewed oil into the Gulf for about three months.

His decision opens with a recap of the disaster. And he even names all of the men killed, even though this case really isn't about the deaths. It's more about civil liability for the damage and the pollution to the Gulf. These are lawsuits that were brought by the U.S. Government, Gulf states and private plaintiffs. Barbier had heard evidence at a trial last year and now is finally concluding that BP's conduct was reckless. It was a substantial cause of the blowout, the explosion and the resulting oil spill. He also assessed blame for the disaster between BP and its contractors on the well. He ruled that BP is 67 percent responsible. The rig owner, Transocean, bears 30 percent. And cement contractor Halliburton takes 3 percent.

CORNISH: Meanwhile, this is part of a complicated multi-phased civil trial that's been going on. I mean, put this in context for us in terms of how the case goes from here.

ELLIOTT: Well, this is really all about the price tag. This is significant because it means BP now faces pollution fines that will be nearly quadruple what it would have been assessed if the judge had found simple negligence. See, under the Clean Water Act with the higher bar of gross negligence, BP can be fined up to $4,300 per barrel of oil discharge. That is still a subject of dispute - how much oil fouled the Gulf. The government estimates more than 4 million barrels of oil. BP says it was more like 2.5 million. So that figure will be critical when Barbier finally decides it - whether or not BP is going to be paying a $10 billion fine or now up to $18 billion. And Barbier, in January, has a phase of the trial set to determine that.

CORNISH: What's been the reaction from the parties in the case today?

ELLIOTT: You know, BP put out a statement saying it strongly disagrees with Barbier's ruling and will immediately appeal to the Fifth U.S. Circuit Court of Appeals. It said, quote, "the law is clear that proving gross negligence is a very high bar. And that was not met in this case."

In Washington D.C. today, U.S. Attorney General Eric Holder spoke of the ruling. He said that the Justice Department was very pleased with it.

ERIC HOLDER: The largest oil spill in United States history was caused by BP's gross negligence and willful misconduct. The court's findings will ensure that the company is held fully accountable for its recklessness. And we are confident that this decision will serve as a strong deterrent to anyone who is tempted to sacrifice safety and the environment in the pursuit of profit.

ELLIOTT: Now, here on the Gulf Coast people are anticipating that penalty money because, you know, Congress did pass a law that 80 percent of the Clean Water Act fines will come back to Gulf Coast communities to restore the economy and the environment.

CORNISH: Debbie, thank you.

ELLIOTT: Thank you, Audie.

CORNISH: That's NPR's Debbie Elliott talking about a federal judge's ruling that BP was grossly negligent in the Deepwater Horizon oil spill in the Gulf of Mexico. Transcript provided by NPR, Copyright NPR.